Firearm with exchangeable barrels

ABSTRACT

A firearm in the nature of a rifle with a plurality of exchangeable barrels, any one barrel being adapted to be threadedly connected to the receiver of the action. Thus, barrel replacement is accomplished by retraction of a set screw and unthreading of one barrel from the receiver and, thereafter, threading of a second barrel in its place and tightening of the set screw, once proper receiver-barrel alignment is achieved. Barrel exchange is accommodated by a depressible stock insert which yields to dimensional variations of each barrel during barrel removal and replacement. A wrench-receiving counterbore at the distal end of each barrel permits suitable tightening of each barrel prior to firing. Barrel alignment is achieved by use of alignment markings on the distal end of the receiver and the proximal end of each barrel.

United States Patent [191 Low [451 Oct. 22, 1974 FIREARM WITH EXCHANGEABLE BARRELS [76] Inventor: Garth R. Low, 766 Princeton Dr.,

Midvale, Utah 84047 [22] Filed: Dec. 3, 1973 [21] Appl. No.: 421,194

[52] US. Cl 42/75 B, 42/76 R [51] Int. Cl F4lc 21/00, F4lc 23/00 [58] Field of Search 42/75 B, 77, 76 R, 71 R Primary ExaminerBcnjamin A. Borchelt Assistant Examiner-C. T. Jordan Attorney, Agent, or Firm-Lynn G. Foster 57 7 ABSTRACT A firearm in the nature of a rifle with a plurality of exchangeable barrels, any one barrel being adapted to be threadedly connected to the receiver of the action. Thus, barrel replacement is accomplished by retraction of a set screw and unthreading of one barrel from the receiver and, thereafter, threading of a second barrel in its place and tightening of the set screw, once proper receiver-barrel alignment is achieved. Barrel exchange is accommodated by a depressible stock insert which yields to dimensional variations of each barrel during barrel removal and replacement. A wrench-receiving counterbore at the distal end of each barrel permits suitable tightening of each barrel prior to firing. Barrel alignment is achieved by use of alignment markings on the distal end of the receiver and the proximal end of each barrel.

7 Claims, 5 Drawing Figures FIREARM WITH EXCHANGEABLE BARRELS BACKGROUND l. Field of Invention The present invention relates generally to firearms and more particularly to a firearm with a plurality of exchangeable barrels.

2. Prior Art Prior proposals for use of a single stock and action together with multiple barrels or any one of several removable barrels have been extensive, inconvenient to accomplish barrel exchange, resulted in damage to the exterior of removable barrels, involved complex mechanisms for barrel exchange and have lacked eye appeal, bearing at best little relationship to the appearance of conventional firearms.

BRIEF SUMMARY AND OBJECTS OF THE INVENTION The present invention provides a firearm with exchangeable barrels', each barrel being removably threaded into the action and there anchored in correct alignment. Tightening is accomplished using a male wrench in a correspondingly configurated counterbore at the distal end of each barrel. A'depressible stock insert permits barrel displacement during exchange.

It is a primary object of the present invention to provide an improved firearm.

It is another paramount object of the present invention to provide a novel firearm in connection with which any one of several exchangeable barrels may be utilized.

It is another important object of the present invention to provide a novel firearm utilizing a removable barrel threaded to the action and removably anchored in proper alignment.

Another significant object of the present invention is the provision of a novel firearm the barrel of whichis removable and tightened in place using a male wrench in a correspondingly configurated counterbore at the distal end of the barrel.

Another and no less important object if the present invention is the provision of an improved firearmwith a removable barrel, barrel removal being accommodated by a depressible stock insert.

These and other objects and features of the present invention will be apparent from the followingdetailed description, taken with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective of one presently preferred firearm embodiment, in the form of a rifle, according. to the present invention;

FIG. 2 is an exploded fragmentary enlarged perspective of the firearm of FIG. 1;

FIG. 3 is an end view taken along line 33 of FIG. 1;

FIG. 4 is a cross sectional view taken along line 4-4 of FIG. 1; and

FIG. 5 is a fragmentary view showing the threaded connection between the barrel and the receiver of the action.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT While it is to be appreciated that the present invention has application in a broad range of firearms, the Figures illustrate a rifle embodiment generally designated 10. Except as hereinafter explained, the rifle 10 comprises a conventional stock 12 equipped with a shoulder plate 14 and a barrel cradle recess 16. The stock 12 is also equipped with a generally rectangular cavity 18 opening centrally at the top of the stock rearward of the cradle recess 16 and forward of the bolt action recess 20 of the stock. The recess 20 in a conventional way receives action 22, which includes a bolt 24 equipped with a handle 26. The bolt 24 is equipped with an ejector 28 and would normally conceal a magazine (not shown) extending downward into the stock at the action recess 20. A trigger 30 conventionally projects out of the bottom of the stock and is sheltered by a trigger guard 32, both in a conventional manner. The action 22, trigger 30 and trigger guard 32 are retained in the indicated position in a conventional manner using screws and the like. The rear collar 34 of the receiver 36 is shown as having a peep sight 38 conventionally mounted thereon, although it is to be appreciated that any type of sight, including a telescope may be appropriately associated with the rifle 10. The forward collar 40 comprises a threaded side bore 42, into which a set screw 44 is appropriately placed for purposes and in a manner hereinafter more fully described. The forward collar 40 of the receiver 36 also includes an alignment mark 46 by which the yet to be described barrel is properly positioned once connected to the receiver.

The cavity l8'of the stock 12, as best seen in FIG. 4 comprises an essentially horizontal base surface 50 and spaced parallel vertical side wall interior surfaces 52 each comprising part of a side wall 54 of the stock 12. The base 50 comprises two blind bores 56 having a central conical recess 58. Each conical recess 58 receives one axially directed pointed end 60 of two compression springs 62, the springs 62 being sized and shaped so that the coils diametrally fit within recess 58.

The two springs 62 comprise part of a barrel displacement-accommodating stock insert assembly 64; The assembly comprises insert 66, the side edges 68 being spaced a distance slightly greater than the spacing between the wall surfaces 52 and parallel one to another but each perpendicular to the base 69 of the insert 66. The insert 66 also comprises a forwardly convergent rounded and tapered barrel cradling recess 72. The base surface 69 is shaped at two locations with annular recesses 74 into which the top coiled end of one spring 62 rests. Thus, once the barrel is assembled to the receiver, the insert 66'assumes the position illustrated in FIG. 4. However, to accommodate barrel removal, the insert 66 may be depressed counter to the force of compression springs 62 in a manner hereinafter more fully described.

The rifle 10 comprises an exchangeable barrel 80, which may be replaced by any one of several additional barrels, the plurality of barrels being of various calibers, depending-upon availability and the wishes of the purchaser. The barrel comprises a conventional lining 82 defining a conventional bullet projecting bore and an enlarged exposed proximal end portion 84. The proximal end portion 84 terminates in threads 86 of a reduced diameter, which are threadedly joined to threads 88 (FIG. 5) of the collar 40, at the interior surface thereof. An alignment mark 90 at the proximal portion 84 is formed, after the unit hasbeen manufactured and tested, directly adjacent the previously mentioned alignment mark 46 so that the lay user-may disassemble and reassemble the rifle using one or more exchangeable barrels 80, without disturbing the accuracy of projectiles issuing from each barrel 80.

The exterior of the barrel 80 is sharply tapered at 92, which in the assembled condition rests within the forwardly convergent recess 72 of the stock insert 66. The barrel 80 also comprises an elongated central portion 94, which is also tapered but to a lesser degree than taper 92. The distal end 96 of the barrel 80 is shown as having a front sight 98 appropriately and conventionally mounted thereto. The bore lining 82 terminates a short distance, preferably on the order of less than one inch, from the terminal face 100 at the distal end 96. A polygonal counterbore 102 is disposed forward of the distal terminal site of the lining 82, as best shown in FIG. 3, and is adapted to receive a similarly shaped wrench, accommodating tightening of a barrel 80 being assembled to the rifle 10, to facilitate a tight threaded connection at 86-88 and to cause alignment marks 46 and 90 to be placed side by side as illustrated in FIG. 1, or loosening of a barrel 80 being removed from the rifle 10. Clearly, by utilization of the wrench counterbore 102 and a correspondingly shaped wrench, damage to the barrel is minimized and any scoring or the like which occurs is concealed from the human eye within the counterbore 102. The rifle 10, independent of the caliber of any barrel 80 associated therewith appears to the eye to be essentially a conventional firearm, any barrel 80 being secured in the assembled condition using the set screw 44 properly advanced in the threaded bore 42 of the collar 40 such that, with the alignment marks 46 and 90 as shown in FIG. 1, the interior tapered end 104 of the set screw 44 seats within a root 106 of threads 86.

The use of the rifle 10 is conventional and need not here be described. However, when the user desires to change from a barrel 80 of one caliber to a barrel 80 of another caliber, a screw driver or Allen wrench is placed within a slot or recess at the exposed face of the set screw 44 and the set screw is withdrawn along the threaded bore 42 until the tapered tip 104 clears the threads 86. A wrench is non-rotatably fitted within the wrench counterbore 102 at the distal end 96 of the barrel 80 being removed. The wrench is rotated in a clockwise direction as viewed in FIG. 1 causing the threads 86 to move forward in respect to the threads 88. After the threaded connection 86-88 is initially loosened, the rotation may be continued by hand until the threads 86 of the barrel 80 clear the receiver threads 88. As the barrel 80 being removed is advanced within the threads 88, the stock insert 66 is depressed by reason of engagement with the barrel taper 92, thereby accommodating the withdrawal. Once the withdrawal has been completed, the springs 62 return the insert 66 to its extended position illustrated in FIG. 4. An additional barrel 80 may then be assembled to the remainder of the rifle 10 by repeating the indicated steps in reverse.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by United States Letters Patent is:

1. A firearm comprising: stock means; means mounted to the stock means for receiving and firing a cartridge, including trigger means, said mounted means comprising an axial threaded bore at the distal end thereof; removable and exchangeable barrel means having an axial reduced diameter threaded proximal end, sized and shaped to be matingly connected to the mounting means by the threads of the bore at the distal end thereof, the stock means comprising recess means supporting the barrel means adjacent said threaded connection, at least a portion of the barrel means being exteriorly forwardly convergently tapered and supported by the recess means of the stock means; said stock means further comprising a biased depressible section defining at least part of the recess means and depressible respecting the remainder of the stock means to permit axial movement of the barrel means to accommodate said tapered exterior barrel means surface during removal and connection of the barrel means to the mounted means.

2. The firearm of claim 1 wherein the distal end of the mounted means comprises a threaded bore oriented essentially normal to the axis thereof and further comprising set screw means removably threaded into said normal threaded bore and extending to the root of spaced threads at the proximal end of the barrel means.

3. The firearm of claim 1 further comprising juxtaposed alignment marks respectively carried by the barrel means and the distal end of the mounted means to insure alignment therebetween.

4. The firearm of claim 1 wherein the biased depressible stock section comprises an insert disposed within a correspondingly shaped cavity of the remainder of the stock means and resilient means with memory interposed between the base of the insert and the base of the cavity urging the insert against the barrel means at the recess means thereof but permitting depression of the insert during axial barrel means displacement.

5. A firearm comprising:

stock means;

means mounted to the stock means for receiving and tiring a cartridge, including trigger means, said mounted means comprising an axial threaded bore at the distal end thereof;

movable and exchangeable barrel means having an axial reduced diameter threaded proximal end, sized to be matingly connected to the mounted means by threads of the bore at the distal end thereof, the stock means comprising recess means supporting the barrel means adjacent said threaded connection;

said barrel means comprising a wrench-receiving female counterbore exposed at the distal end of the barrel means in axial alignment with and larger in transverse size than the bore of the barrel means, whereby the barrel means may be loosened and tightened in respect to the mounted means by using a wrench in the female counterbore.

threadedly connecting the proximal end of the barrel to the distal end of the receiver; and

tightening the threaded connection by placing a male wrench in a female wrench-receiving counterbore disposed along the axis of the barrel and exposed at the distal end of the barrel, and rotating the wrench and barrel. 

1. A firearm comprising: stock means; means mounted to the stock means for receiving and firing a cartridge, including trigger means, said mounted means comprising an axial threaded bore at the distal end thereof; removable and exchangeable barrel means having an axial reduced diameter threaded proximal end, sized and shaped to be matingly connected to the mounting means by the threads of the bore at the distal end thereof, the stock means comprising recess means supporting the barrel means adjacent said threaded connection, at least a portion of the barrel means being exteriorly forwardly convergently tapered and supported by the recess means of the stock means; said stock means further comprising a biaSed depressible section defining at least part of the recess means and depressible respecting the remainder of the stock means to permit axial movement of the barrel means to accommodate said tapered exterior barrel means surface during removal and connection of the barrel means to the mounted means.
 2. The firearm of claim 1 wherein the distal end of the mounted means comprises a threaded bore oriented essentially normal to the axis thereof and further comprising set screw means removably threaded into said normal threaded bore and extending to the root of spaced threads at the proximal end of the barrel means.
 3. The firearm of claim 1 further comprising juxtaposed alignment marks respectively carried by the barrel means and the distal end of the mounted means to insure alignment therebetween.
 4. The firearm of claim 1 wherein the biased depressible stock section comprises an insert disposed within a correspondingly shaped cavity of the remainder of the stock means and resilient means with memory interposed between the base of the insert and the base of the cavity urging the insert against the barrel means at the recess means thereof but permitting depression of the insert during axial barrel means displacement.
 5. A firearm comprising: stock means; means mounted to the stock means for receiving and firing a cartridge, including trigger means, said mounted means comprising an axial threaded bore at the distal end thereof; movable and exchangeable barrel means having an axial reduced diameter threaded proximal end, sized to be matingly connected to the mounted means by threads of the bore at the distal end thereof, the stock means comprising recess means supporting the barrel means adjacent said threaded connection; said barrel means comprising a wrench-receiving female counterbore exposed at the distal end of the barrel means in axial alignment with and larger in transverse size than the bore of the barrel means, whereby the barrel means may be loosened and tightened in respect to the mounted means by using a wrench in the female counterbore.
 6. The firearm of claim 5 wherein the female counterbore is polygonal in configuration.
 7. A method of assembling a barrel to a receiver carried by a stock, comprising the steps of: advancing a separate barrel generally along its axis toward a receiver carried by a stock; depressing an insert of the stock counter to predetermined bias by a diametrally enlarged proximal end portion of the barrel; threadedly connecting the proximal end of the barrel to the distal end of the receiver; and tightening the threaded connection by placing a male wrench in a female wrench-receiving counterbore disposed along the axis of the barrel and exposed at the distal end of the barrel, and rotating the wrench and barrel. 